One lesson to be drawn: don't open a text file with Excel (or Word or other word processors, for that matter) if you are planning to save it and hope to process it afterwards. MS Office applications are likely to add all kinds of characters (sometimes invisible) or also remove some others which will often ruin subsequent processing, be it in Perl or with any other language.

Text editors (as opposed to word processors) such Notepad++ are good at that because they preserve the text. Uner Windows, you could also use the Crimson Editor, Ultra Edit (shareware), jEdit, etc.